1. Field of the Invention
The present invention relates a chip capable of improving test coverage of chip pads and a method capable of improving test coverage of chip pads, and particularly to a chip and a method that can utilize a controller to control a pad not coupled to a probe to read/write a predetermined datum to improve test coverage of chip pads.
2. Description of the Prior Art
Please refer to FIG. 1 and FIG. 2. FIG. 1 is a diagram illustrating a probe 100 of a test machine utilizing a data compression method to write test data TD to a chip 200 according to the prior art, and FIG. 2 is a diagram illustrating the probe 100 of the test machine utilizing the data compression method to read test data from the chip 200 according to the prior art. As shown in FIG. 1, the probe 100 writes the test data TD to a data path circuit 206 through a pad 202 and an off-chip unit 204. Then, the data path circuit 206 writes the test data TD to a storage unit 208 of the chip 200. As shown in FIG. 2, when the probe 100 utilizes the data compression method to read the test data from the chip 200, the probe 100 can read the test data from a corresponding block of the storage unit 208 through an exclusive-OR gate 210 and the data path circuit 206.
As shown in FIG. 1 and FIG. 2, a chip probing test of the prior art can cover the data path circuit 206, the storage unit 208, the pad 202, and the off-chip unit 204. However, the chip probing test of the prior art can not cover other pads and other off-chip units of the chip 200. That is to say, the chip probing test of the prior art can not determine whether other pads and other off-chip units of the chip 200 are passed.